The packaging and assembly of die (“chips”) is an important in the manufacture of integrated circuits. This packaging process is further complicated when the circuit includes a color sensor since the packaging involves integrating optical components with electronic circuits.
For example, a color sensor needs to be integrated with a color filter (e.g., a pigment filter). Currently, the types of material utilized for the color filter limit the types of filter profiles that can be generated. To address this shortcoming, the integration process typically includes a separate step of attaching glass that is coated with an optical profile that supplements the filtering properties of the color filter.
In one prior art approach illustrated in FIG. 4, glass with a desired filter profile is attached to an encapsulated package. This approach has the following advantages: 1) Filter profile coat on glass are readily available (e.g., standard parts), 2) proven and often used in industry. However, this approach suffers from the following disadvantages: 1) increased packaging costs; 2) tighter process controls for filter attachment process; 3) filter attachment process has a relatively low efficiency, such as a low unit per hour (UPH); and 4) increased total package height since there is an additional thick layer of Glass substrate.
In another prior art approach illustrated in FIG. 5, glass with a desired filter profile is attached in an air gap package. 1) Filter profile coat on glass are readily available (e.g., standard parts), 2) proven and often used in industry, 3) air gap packages are in general robust and have good reliability result. However, this approach suffers from the following disadvantages: 1) increased packaging costs since more piece parts are required; 2) tighter process controls for filter attachment process; 3) filter attachment process has a relatively low efficiency (e.g., a low unit per hour (UPH); 4) increased total package height since there is an additional thick layer of Glass substrate); and 5) air gap package size is limited in terms of miniaturization.
Both of these approaches significantly increase the total package size and also the total cost of the product. Furthermore, the attachment of the glass filter requires tight process control to ensure that the filter is attached in a robust manner and that the filter will not become un-attached in the field.
Based on the foregoing, there remains a need for a method for packaging a photo detector that overcomes the disadvantages set forth previously.